Si8410/20/21
4.2. Input and Output Characteristics
The Si841x and Si842x inputs and outputs are standard CMOS drivers/receivers. Table 12 details powered and
unpowered operation of the Si84xx.
Table 12. Si84xx Operation Table
1,4
1,2,3
1,2,3
1,4
Comments
V Input
VDDI State
VDDO State
V Output
I
O
H
L
P
P
P
P
P
H
L
L
Normal operation.
X
UP
Upon the transition of VDDI from unpowered to
powered, V returns to the same state as V in less
O
I
than 1 µs.
Upon the transition of VDDI from unpowered to
powered, V returns to the same state as V in less
X
P
UP
L
O
I
than 1 µs.
Notes:
1. VDDI and VDDO are the input and output power supplies. VI and VO are the respective input and output terminals.
2. Powered (P) state is defined as 2.375 V < VDD < 5.5 V.
3. Unpowered (UP) state is defined as VDD = 0 V.
4. X = not applicable; H = Logic High; L = Logic Low.
4.3. RF Radiated Emissions
The Si841x and Si842x families use an RF carrier frequency of approximately 2.1 GHz. This will result in a small
amount of radiated emissions at this frequency and its harmonics. The radiation is not from the IC chip but, rather,
is due to a small amount of RF energy driving the isolated ground planes, which can act as a dipole antenna.
The unshielded Si8410 evaluation board passes FCC requirements. Table 13 shows measured emissions
compared to FCC requirements.
Radiated emissions can be reduced if the circuit board is enclosed in a shielded enclosure or if the PCB is a less
efficient antenna.
Table 13. Radiated Emissions
Frequency Measured FCC Spec Compared to
(GHz)
2.094
2.168
4.210
4.337
6.315
6.505
8.672
(dBµV/m) (dBµV/m)
Spec (dB)
70.0
68.3
61.9
60.7
58.3
60.7
45.6
74.0
74.0
74.0
74.0
74.0
74.0
74.0
–4.0
–5.7
–12.1
–13.3
–15.7
–13.3
–28.4
Preliminary Rev. 0.1
21
SILICON [ SILICON ]
